Tories in turmoil as David Davis resigns over 42-day vote

The shadow home secretary, David Davis, threw the Conservative leadership into turmoil today by unexpectedly announcing his resignation as an MP, forcing a byelection in his constituency over the government's 42-day terror detention plan.

Davis's move - to "take a stand" on what he said was the "relentless erosion" of freedoms by the government - was taken against the wishes of David Cameron, who beat him in a Tory leadership election in 2005.

Cameron made his disappointment clear by replacing Davis as shadow home secretary with the shadow attorney general, Dominic Grieve, and saying Davis had no guarantee of returning to the front bench if - as all parties expect - he wins the byelection.

Davis seemed unaware he had consigned himself to the backbenches, telling the BBC: "I may or may not be on the backbenches … This issue matters more to me than my job."

Labour attempted to undercut Davis by announcing that they, like the Liberal Democrats, would not contest the byelection in Howden and Haltemprice. But Davis's decision to resign and stand again - a move last seen on the British mainland in 1982, and not since 1973 on a single issue of principle - injects new unpredictability into British politics.

The bookmakers Ladbrokes said Davis's actions offered a "glimmer of hope" for Labour and promptly cut the odds on a Brown victory at the next general election from 9/4 to 2/1.

In spite of Cameron's swift decision to replace Davis and his apparent lack of enthusiasm for Davis's decision, the Conservatives rejected suggestions there had been a cabinet split on the issue.

Cameron described Davis's stand as "courageous" but emphasised that it was a personal one. He wished Davis well in his campaign and said he and other Conservatives may campaign for him.

But, announcing Grieve's appointment, he insisted: "My responsibility as leader of the Conservative party is to put in place at all times the strongest, best and most permanent team and to offer our country a better government."

Grieve rejected suggestions that the party's stance on the issue had split the shadow cabinet and had been the cause of divisions between Davis and Cameron.

"In all parties there are debates and issues but the idea that this has been some sort of divisive issue is a fantasy," he told Sky News.

He added: "There has never been any split on 42 days of any kind at all within the shadow cabinet; we have united in our view that the measure is unnecessary, wrong, and, in fact with the concessions we have now had, appallingly drafted."

Grieve said the Tories were committed to repealing the legislation as it currently stood.

"If what ends up on the statute book is not in the context of a state of emergency, and at the moment it certainly is not, then we would be wishing to repeal it. The first step is to prevent it going on the statute book in the first place."

Davis also denied that there was any split. Asked whether he had had a disagreement over tactics with Cameron, Davis told the BBC: "It's completely untrue. David has given me a completely free hand on this. He and I have virtually identical beliefs in this area."

A Conservative source said Davis had had only three hours' sleep on Tuesday night and was going through some kind of personal crisis. Davis brushed the suggestion aside, saying: "Pop psychology in politics is very amusing but rarely right."

In his resignation statement, delivered outside the Commons at 1pm, Davis said: "I will argue in this byelection against the slow strangulation of fundamental British freedoms by this government."

He said the undermining of civil liberties through moves such as detention and the introduction of ID cards "cannot go on".

"It must be stopped, and for that reason today I feel it is incumbent on me to take a stand," he told reporters outside the Commons.

Aides to Davis had indicated that last night's vote was "do or die", and he had staked a great deal of his credibility on the outcome.

A spokeswoman for Cameron insisted there was "absolutely no rift" between the two men. But Davis told both Cameron and the Liberal Democrat leader, Nick Clegg, about his decision last night after the terrorism vote.

Clegg said: "The Liberal Democrats have consistently opposed this unnecessary and illiberal proposal [increasing the detention limit] which poses a threat so serious to British liberties that it transcends party politics.

"I have therefore decided, after consultation with the party nationally and locally, that we will not stand a candidate at the forthcoming byelection which will be contested by David Davis solely on this issue."

The Lib Dems had targeted the seat in 2005 as part of its ill-fated "decapitation" strategy to unseat key Tory figures but Davis was re-elected with a 5,116 majority.

Jacqui Smith, the home secretary, said: "Faced with a crucial decision on the safety and protection of the British public, the Conservatives have collapsed into total disarray on what is their first big policy test since they have come under greater scrutiny.

"David Cameron must come clean on what has really happened and why David Davis has really resigned."

The director of Liberty, Shami Chakrabarti, said: "Last night's debate, and the brave Labour rebels in particular, showed that democrats from across the spectrum care passionately about rights and freedoms.

"MPs of all parties hold courage and conviction about these values and few more so than David Davis."

Davis's local party fully backed his decision. Its chairman, Duncan Gilmour, said. "David discussed early in the week what he would do if the result went against us last night. David is a man of principle and we fully back him," he told the Press Association.

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